Air-cushion vehicle with brush support

ABSTRACT

An air-cushion vehicle has a plurality of brushes mounted on the body within the boundary of the downwardly extending peripheral wall or skirt thereof, and extending downwardly to or below the level of the peripheral wall or skirt to support the vehicle while at rest without substantial deformation of the wall or skirt. The individual flexibility of the bristles allows the brushes to pass over obstacles, or to part so as to allow an obstacle to pass therethrough.

United States Patent Ramsey [4 1 May 16, 1972 [541 AIR-CUSHION VEHICLEWITH BRUSH 3,173,509 3/l965 Wemicke et al ..l80/l20 SUPPORT 3,249,1675/1966 Tibbetts ....l80/l27 3,207,245 9/1965 Welland ....180/1 19 [72]Ramsey Aven" 3,208,543 9/1965 Crowley ....180/l2l [73] Assignee: AirCushion Vehicles, Inc., Poestenkill, 3,292,721 12/1966 Dobson ..l80/l20Prima Examiner-A. Ha Lev 22 Fld: Fb.25 190 Y 1 l e e 7 Attorney-Pennie,Edmonds, Morton, Taylor and Adams [2]] Appl. No.: 13,986

[57] ABSTRACT U-S. l6, 20, An ajpcushion vehicle has a plurality ofbrushes mounted on [51] II.-

..B60V the within the boundary of the downwardly extending [58] Field ofSearch ..l80/127, 128, 120, 116, 1 19, peripheral wall or skin h f andextending downwardly to 180/ 121 or below the level of the peripheralwall or skirt to support the I 56] R f Cited vehicle while at restwithout substantial deformation of the e wall or skirt. The individualflexibility of the bristles allows the UNITED STATES PATENTS brushes topass over obstacles, or to part so as to allow an obstacle to passtherethrough. 3,055,446 9/1962 Vaughen ..180/ 127 X 3,172,494 3/1965Cocketell 180/127 1 Claims, 6 Drawing figures i I l 1' l 15 i l g l I 1l5 1 1 1 1 51 l U v 1 1' 1 1 .1 26 26 a 1 PATENTEDMHBM: 3.662.851

' SHEET 1 OF 2 INVENTOR FIG.1

- Harry E. Ramsey BY 94 Q; (awn 2m. @4

ATTORNEYS FIG. 3

PATENTEDMAHSISTZ 3.662.851

Si'iEU 2 OF 2 l ENTOR .Romsey ATTORNEYS Hor BACKGROUND OF THE INVENTIONAir-cushion vehicles utilize an arrangement for producing a cushion ofair under pressure beneath the vehicleso as to raise the vehicle a shortdistance from the supporting surface. The supporting surface may bewater, ground, snow, ice, etc.

Two principal types of structures are commonly employed for producingthe air cushion. One type employs an open plenum chamber beneath thevehicle witha relatively large volume of low pressure air suppliedthereto. The plenum chamber usually is formed of a downwardly extendingperipheral wall or skirt which, together with the bottom of the vehicle,forms a chamber which is open at the bottom. The other principal typeemploys a peripheral slot or jet which produces a downwardly andinwardly sloping curtain of air under relatively high pressure. Usuallythe curtain of. air is produced by supplying air under high pressure toa slot in a peripheral wall or skirt.

The peripheral walls or skirts are frequently sufficiently deformable sothat, when the vehicle encounters surface obstructions, the wall orskirt can flex without being ruptured. Flexible or semi-rigid materialsare frequently used for the wall or skirt.

If, when the vehicle is at rest for long periods of time, the

weight of the vehicle is supported by the wall or skirt, a permanent orsemi-permanent deformation of the wall or skirt may result. This mayadversely affect the performance of the air cushion, and in any eventwill alter the clearance of the vehicle from the supporting surface.

In the past, various means have been provided for holding the vehicleoff the ground while at rest, such as retractable skids and the like.While such expedients may be effective to prevent adverse deformation ofthe wall or skirt, the retracting mechanism adds to the complexity,weight and cost of the vehicle. This is undesirable, particularly insmall vehicles. On the other hand, if the supports are not retractableand are left in place below the skirt level, they may interfere withnormal operation, particularly over rough terrain.

The present invention provides a simple and inexpensive means forsupporting the vehicle when at rest, which does not require retractionand yet does not interfere with normal operation of the vehicle.

SUMMARY OF THE INVENTION In accordance with the invention, a pluralityof brushes are attached to the body of the air-cushion vehicle withinthe boundary of the peripheral wall or skirt and extending downwardlyapproximately to the lower edge of the wall or skirt. The brushes aresufficiently stiff so that they are capable of supporting the vehiclewhile at rest without substantial deformation of the peripheral wall orskirt. However, inasmuch as the bristles of the brushes are elastic, ifthe brushes strike projections or obstacles in normal operation of thevehicle, the bristles bend or part so as to pass over or around theobstacle without injury, and without impairing the operation of thevehicle.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE SPECIFIC EMBODIMENTReferring to the figures, an air-cushion vehicle is shown of the typedescribed in detail in application Ser. No. 2,810, filed Jan. 14, 1970by Hugo S. Ferguson for Air Cushion Vehicles", assigned to the sameassignee as the present application. A body platform has an airpropeller ll driven by motor 12. Front and rear sets of steering vanes14 and 15 are controlled by a steering wheel 16. The downstream flow ofair from the propeller, under the control of the front steering vanes14, passes through air channels on either side of the operator position(behind steering wheel 16) to the rear steering vanes.

The body platform 10 is provided with a downwardly extending peripheralwall or skirt 21 which forms an open plenum chamber 22 beneath thevehicle. As described in the above-identified application, air from thelower portion of the propeller is admitted to the plenum chamber throughan opening in the body platfonn 10 (not shown).

Advantageously, the body platform 10 is molded of foamed, closed-cell,rigid polyurethane with a tough skin, and the peripheral wall or skirt21 is formed of foamed, closed-cell, semi-rigid polyethylene. Thesemi-rigid wall has sufficient flexibility to avoid serious damagewhentraveling over rough terrain.

Although the semi-rigid skirt 21 has sufficient elasticity to return toits original condition after being deformed in normal operation, if theweight of the vehicle rests on the skirt for a considerable length oftime the skirt will be more or less permanently deformed or set". Thiswill result in changing the clearance of the vehicle from the ground orother supporting surface. Further, if chambers or slots are formed inthe skirt, the resulting deformation may seriously affect subsequentperformance.

Accordingly, brushes 23 are attached to the vehicle body in a suitableconfiguration to provide stable support when the vehicle is at rest. Theuse of three round brushes, as shown, has been found satisfactory, butthe number and shape of the brushes may be selected as meets therequirements of a particular vehicle. The brushes may be attached to thebody of the vehicle in any suitable manner. The brushes projectapproximately to the lower edge of skirt 21. If they project slightlybelow the lower edge, when the vehicle is on level ground the skirt willbe slightly above the surface. If the brushes do not extend quite to thelower edge, the wall need give only a little bit and the vehicle willthen be resting on the brushes. This may be satisfactory in particularapplications.

In the specific embodiment shown, a perforated plate 25 with threadedcylinder 26 welded thereto is inserted in the body platform 10 duringthe molding operation. The head 24 of the brush has a central holetherethrough, and a bolt 27 and washer secure the brush in a recess 28in the body of the vehicle.

The brushes 23 are designed to have sufficient stiffness to support theweight of the vehicle. Bristles of nylon and polypropylene have beenemployed with success, and bristles of wire, such as stainless steel,may be employed if desired. The size of the brush, diameter and lengthof the bristles, and the bristle material may be selected as meets therequirements of a particular application.

In one brush which has been used with success, approximately tufts ofbristles were set in 1% inch holes in a plywood back 24 about 8 inchesin diameter and 1 inch thick. Nylon bristles about 55 mils (thousandthsof an inch) in diameter were used. Each tuft had about 56 bristles andthe length of the tufts was 4% inches from the back. Three of thesebrushes provided satisfactory support for a 250 pound vehicle. Thebrushes were mounted so that the bristles extended about one-quarterinch below the level of the skirt.

Similar brushes having ripple polypropylene bristles have also been usedwith success. A ripple bristle is shown in FIG. 5. As indicated in FIG.6, the filament forming the bristle may be somewhat fluted. With suchbristles, the ripples tend to insure contact between adjacent bristlesso as to increase the overall stiffness of the brush without reducingthe flexibility of the individual bristles.

It is possible for the bristles of the brushes to acquire a set if thevehicle is left standing for a long time with the bristles somewhatbent. This might occur, for example, if the vehicle were dragged alongthe ground to its resting place, and left standing without raising it toallow the bristles to resume their normal straight condition. Althoughsuch bending may not be serious, the bending may be reduced or avoidedby strengthening the brush as a whole.

FIG. 4 shows an elastic band 29 encircling the brush near the base ofthe bristles, so as to strengthen the bristles as an aggregate againstbending, while still allowing individual bending of the bristles as maybe required to enable them to pass over obstacles, or to part so as toallow smaller obstacles to pass thercthrough.

If desired, the bristle diameter may be increased, say to 7$ inchdiameter or more, particularly with longer bristles, to form a stifferbrush while still retaining adequate flexibility to pass over or aroundobstacles.

lclaim 1. An air-cushion vehicle including a body having a deformableperipheral wall or skirt of impermeable material extending downwardlytherefrom and means for producing an air cushion beneath said bodywithin the confines of said peripheral wall or skirt for raising thevehicle above a supporting surface, in which the improvement comprises aplurality of discrete separated support brushes fixedly mounted on theunder side of said body a substantial distance inwardly of the boundaryof said peripheral wall or skirt and spaced therefrom, said brushesextending downwardly and terminating in a plane at a level below themajor portion of said peripheral wall or skirt and approximately at thelevel of the lower edge of said peripheral wall or skirt for supportingsaid vehicle in the absence of said air cushion, each said brushcomprising a plurality of individually flexible bristles, the aggregateof said bristles providing stiff brushes for the said support of saidvehicle.

0' l l t l

1. An air-cushion vehicle including a body having a deformableperipheral wall or skirt of impermeable material extending downwardlytherefrom and means for producing an air cushion beneath said bodywithin the confines of said peripheral wall or skirt for raising thevehicle above a supporting surface, in which the improvement comprises aplurality of discrete separated support brushes fixedly mounted on theunder side of said body a substantial distance inwardly of the boundaryof said peripheral wall or skirt and spaced therefrom, said brushesextending downwardly and terminating in a plane at a level below themajor portion of said peripheral wall or skirt and approximately at thelevel of the lower edge of said peripheral wall or skirt for supportingsaid vehicle in the absence of said air cushion, each said brushcomprising a plurality of individually flexible bristles, the aggregateof said bristles providing stiff brushes for the said support of saidvehicle.